Nor Khairina Batrisya Zul Khairi, and Nur Aini Mohd Arish@Arshad. “Development of PH Meter With Solar Panel As Battery Replacement of Lithium Button Cell”. Progress in Engineering Application and Technology 3, no. 1 (June 19, 2022): 147–155. Accessed March 12, 2026. https://penerbit.uthm.edu.my/periodicals/index.php/peat/article/view/6434.